The First Minister’s call came after Labour and Lib Dem leaders said their members would be free to back a Yes vote in an Indyref rerun.

Sturgeon goaded her opponents by highlighting opinion polls showing growing support for independence in the year since 55 per cent of Scots said No.

She said: “They know what way the wind is blowing.”

The SNP leader pointed to comments by Labour’s Kezia Dugdale and the Lib Dems’ Willie Rennie in recent days.

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Both were forced to concede that many in their parties wanted to explore the case for independence.

Sturgeon told a Scottish Parliamentary Journalist Association function: “If what they said is to be credible then they have to take it to the logical conclusion.

“It won’t cut much ice among supporters of independence in their own parties to say in one breath that if there’s another referendum you can stand up for what you believe in but in the next breath say a referendum should be ruled out for ever and a day.

“So my challenge to Kez and to Willie is this … if we do see opinion shift and we do see a material change in circumstances then it would be wrong for any politician to rule out a referendum indefinitely.”

Prime Minister David Cameron has already ruled out any quick – and legal – return to the constitutional question.